1st international round robin test on safety characteristics of hybrid mixtures

Spitzer, Stefan H.; Askar, Enis; Benke, Alexander; Cloney, Chris T.; D’Hyon, Sebastian; Dufaud, Olivier; Dyduch, Z.; Gabel, Dieter; Geoerg, Paul; Heilmann, Vanessa; Jankůj, Vojtěch; Wang, Jian; Krause, Ulrich; Krietsch, Arne; Mynarz, Miroslav; Norman, Frederik; Skřínský, Jan; Taveau, Jérôme; Vignes, Alexis; Zakel, Sabine; Zhong, Shengjun

doi:10.1016/j.jlp.2022.104947

Cited by 9 publications

(1 citation statement)

References 4 publications

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“…There is no internationally recognised standard for determining the technical safety characteristics of hybrid mixtures. In the development of a new standard, first results from parametric studies in a joint research project in Germany have led to a state-of-the-art procedure that can be adopted by laboratories already testing dust explosions in a 20 L explosion chamber [22]. In a round robin test of hybrid mixtures, with methane as the gas component and specific corn starch as the dust sample, the practicality of the procedure, the scatter of results and the variance between test facilities in different laboratories were investigated.…”

Section: Introductionmentioning

confidence: 99%

Parameters Affecting the Explosion Characteristics of Hybrid Mixtures Arising from the Use of Alternative Energy Sources

Helegda,

Pokorny,

Helegda

et al. 2024

Fire

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Explosions of hybrid mixtures are an interesting theoretical and experimental problem in explosion sciences, because they combine the physicochemical properties of flammable gases and dusts. A hybrid mixture is composed of at least two substances in two or more states. The influence of the common presence of flammable gas on the explosiveness parameters of the combustible dust itself is proven. In this study, we present the effect of higher initiation temperatures, different initial sources of initiation with different energies, and the effect of the volume of explosion chambers on the explosions of hybrid mixtures arising from the use of alternative energy sources. The experiments were carried out in 20 L and 1.00 m3 explosion chambers (according to EN 14034-1+A1:2011–EN 14034-4+A1:2011). The accredited method of the Energy Research Centre, VSB-TU Ostrava, for tests was used. The goal is to approximate the behaviour of these systems under different initiation conditions so that it is possible to avoid excessively conservative or overly optimistic results, which then affect the determination of explosion parameters for practical use. It was found that the volume of the explosion chambers in combination with the used initiation source has a fundamental influence on the course of the explosion characteristics.

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Section: Introductionmentioning

confidence: 99%

Parameters Affecting the Explosion Characteristics of Hybrid Mixtures Arising from the Use of Alternative Energy Sources

Helegda,

Pokorny,

Helegda

et al. 2024

Fire

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Decoupling pyrolysis and combustion of organic powders to determine the laminar flame speed

Pietraccini,

Santandrea,

Glaude

et al. 2024

Can J Chem Eng

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Determining the laminar flame speed of dusts is far from straightforward. A strong dependency on the experimental setup and the data treatment's high complexity makes it a true challenge. This work compares three complementary experimental setups to measure the laminar flame speed of organic dust (here, cellulose): a modified Hartmann tube, a 20 L sphere, and a micro‐fluidized bed (MFB) burner. The first two consider the flame propagation phenomenon in its globality, which means that numerous steps are involved simultaneously (particle heating, pyrolysis, oxidation, radiative transfer, flame stretching), while the third one decouples pyrolysis and combustion, to focus mainly on the oxidation rate. An MFB was conceived to generate pyrolysis products and burn them in a laminar flame. Unstretched flame velocities determined with the first two setups were consistent and equal to 22.0 and 26.6 cm ∙ s−1, respectively. Using Silvestrini's equation, values ranging between 14.0 and 33.4 cm ∙ s−1 were obtained according to the dust concentration. With the MFB burner, the flame speed was much higher (135–155 cm ∙ s−1), due to the higher temperature of the fresh mixture and the fact that only the oxidation of the pyrolysis gases is considered. A numerical simulation (Chemkin) confirmed these results since the range 135 to 231 cm ∙ s−1 was obtained for equivalence ratios of 0.6 and 1.2, respectively. The discrepancy between the laminar flame speed determined in the sphere or in the tube and that obtained in the MFB highlights the significant influence of particle heating and pyrolysis during a dust explosion.

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